1. Field of the Invention
The present invention is related to multi-graphics processing unit (GPU) systems, and more particularly to saving power in multi-GPU systems.
2. Background Art
Some graphics processing systems include multiple graphics processing units (GPUs) to allow for performance gains through parallel processing of graphics tasks. For example, a graphics-intensive game may be running that requires or can benefit from having the additional processing power provided by using multiple GPUs. Other applications, however, do not benefit from such increased processing power. When these applications are being run, one or more GPUs may not be used.
In some operating systems, to save power, unused GPUs can be shut down. When the shut down GPUs are re-activated, however, the operating system often executes plug-and-play processes that diminish the user's experience. For example, switching between shut down and active states can lead to long screen freezes and flushes. Alternatively, GPUs can be left in an idle state. In the idle state, known methods, such as clock gating and power gating, can be used to decrease the amount of power that the GPU uses. These methods, however, require multiple circuit blocks of the idle GPU to remain active so that the GPU can be brought back to an active state when it is needed.
What is needed, then, are methods and systems that allow for power to be optimally saved when portions of a GPU or the entire GPU is not used.